Manufacture of diaphragms



Sept. 9, 1947. F. v. SANDER ET AL MANUFACTURE OF DIAPHRAGMS Filed March 24;. 1944 FPA NK MSANDEE Cl/FFOQD A. (01 E6 INVEN TORS ATTORNEY Patented Sept. 9, 1947 MANUFACTURE OF DIAPriRAGMs Frank V. Sander, Highland Park, and Clifiord H. Coles, North Plainfield, N. J., assignors to Ortho Pharmaceutical Corporation, a corporation of New Jersey Application March 24, 1944, Serial No. 527,900

'4 Claims. (Cl. 18-475) I This invention relates to the manufacture of diaphragms of the type particularly suitable as, and sometimes called, pessaries.

Diaphragms of this character are customarily thin walled rubber diaphragms reinforced by a spring at the base and heretofore havebeen made by molding or dipping. In the latter case the diaphragm was made by dipping a mold into a liquid rubber such as latex and a spring was then coated with an adhesive placed upon the mold and rolled up in the skirt of the diaphragm toward the dome. i

It has been found that diaphragms made of thin flexible resilient sheets of plastic materials,

' have certain advantages over those made of rubber. For example, plastic diaphragms are more resistant to many therapeutic agents and solvents found in creams or jellies frequently used in conjunction with diaphragms, which agents and solvents react detrimentally upon rubber. In addition certain of the flexible resilient plastics obtainable in liquid form such as plasticized vinyl resins with solvents or other synthetic or- --ganic polymers (for example only), when in sheet form have suflicient resiliency and elasticity for diaphragm use and are tougher and more durable when so used than rubber. The production of diaphragms from such plastics in liquid form involves certain manufacturing problems because most if not all plastics suitable for diaphragm use adhere strongly to other objects such as molds but do not cohere or stick to themselves. This characteristic introduces great difiiculties in manufacture because diaphragms of this nature are usually provided at the rim or edge with a coiled continuous circular metallic spring, preferably if not necessarily embedded or entirely encased by the material of the diaphragm. This embedding is usually accomplished by rolling the spring in the wall or skirt ofthe diaphragm. In the manufacture of rubber diaphragms by the dipping process it is customary to clip a mold in latex and form a dome and a skirt portion which is later rolled up about this spring. As previously stated, most if not persions.

' this invention; A

Fig. 2 is a vertical transverse section through the same mold illustrating the second step carrying out the method of this invention;

Fig. 3 is a view similar to Fig. 2 and illustrates the next step in practicing this invention; and

Fig. 4 is a side elevation of the finished diaphragm stripped from the mold and resulting from the method of this invention.

In following the process of this invention a mold I is employed, the closed end 2 of which has the desired shape of the finished diaphragm. Adjacent this latter end the mold is provided with an annular groove 3 for receiving a coiled spring 4 after it is rolled as will be hereafter described. At a distance above groove 3, preferably three or four complete turns of the spring above, the mold is provided with a second but relatively shallow groove 5 of sufficient depth only to retain the spring in position and prevent its movement along the mold by its own weight. Any other satisfactory device, such as protrusions or rings may be employed to retain the spring in position.

As previously stated diaphragms of the character of this invention are provided around their lip or margin with a coiled metallic spring 4 arranged in a continuous circle. In practicing this invention such a spring 4 is first placed upon the mold I in position in the groove 5. No adhesive is applied to the spring. The mold is then slowly dipped in a liquid form of the desired plastic, said liquid being at the desired consistency and temperature, until the plastic touches the spring. The mold is then slowly withdrawn and preferably inverted until the coating or film 6 formed by the dipping is dried or solidified. It is preferred to dip the mold to a depth just suflicient to contact the coiled spring. This causes the first layer or coating to be anchored to the'spring. In some instances where the plastic is particularly adherent to the mold after drying it may be preferred to dip the mold somewhat deeper so as to cause the plastic to enter the convolutions of the coiled spring thus causing the first coating or layer to be more firmly anchored to the spring. This first dipping serves the dual purpose of attaching the spring so that it may be rolled with the apron and also provides one coating of the diaphragm wall, all in one operation. -Af-ter drying the-mold is again dipped'a sufficient number of timesto produce the desired wall thickness of plastic upon the mold. Preferably after each dipping the mold is again inverted, spun if desired, and then dried in a warm oven in a moderate air-circulation After the wall thickness has just about-reached the desired thickness andaften drying, thercoiled spring is rolled along themol-d in the skirtportion toward the dome end whereby the skirt portion of the thus formed diaphragm is .pickedup.

and. rolled about the spring completely enclosing the latter. although the plastic adheres tightly to the mold 4 menting the spring to the skirt before and after rolling.

It will be apparent to those skilled in the art from the foregoing that by following the teachings of the above invention the usual steps of cementing a spring to the skirt .portion of the "diaphragm has been eliminated and that other advantages will result from following this invention. It will also be apparent that minor variations may be made in the methods described without-departing from the spirit and scope of -.-.this inv,ention asdefined in the appended claims.

We. claim:

.1. The :method of making diaphragms which :consists in ,the steps of positioning a circular V springat a. predetermined position upon a mold,

This rolling is possiblebecause the end of the coating of plastic is firmly'at- .tached and anchored to the springby the 1 former .step of dipping. This rolling is-cornplete-lwhen the spring .reaches the v groove 3. As heretofore gstated thedistance rbetween grooves .3 and 5 is vsueh that the coiled spring will make: the desired number .of complete revolutions. 0-ther wise -t-herewouldlbe a tendencyfor the spring to con .tinuerotating after the finished di-aphrag-mwas removedandthere must :be no strain uponthe spring, i. e., tendency toward further rolling, twhen'itis'inthe groove :3 in order that the' wall .of 1the"diaphragm willidepend from thespring at the proper point after the:diaphrag-m-is' re- .rnoved from -the -mold.

After the skirt has been rolled;and=the cov- .eredtspring orzbead is resting in groove '3 the :rnoldis again-dipped into thegplasticito a point -retainingthe spring in said position on the mold, dipping the mold while retaining the spring in said position into a liquid plastic of a synthetic organic polymer toa depth until the spring is con- ;tactedby the plastic, removing the .mold 'from the plastic to forma coating or Ithep'lastic von the mold, ,p ermittingjthe, mold. and coating Itosolidify sufiicient1y.,to..anchor the spring to .the coating, rolling jthespring on "the skirt portion ofsaid coating with the spring thereintowardlthejdome1a predetermined number of complete turns, jthere- .aferperrnitting said coating to completely solidify .thus sealing the spring and skirtin rolledposigout/10h, and removing the completed .diaphr-agm where the final 'coat-ing'engages the-rolled bead tosealthe spring-in its rolled position andthus iprevent-unrolling thereafter. This:last dipping also-serves adual-purpose, i. e., it seals=the-rolled spring-and adds to the Wallthickness oftheidi- -,.aph=ragm in .a single operation. After 'again dry- ;ing the diaphragm is removed from the 'mold. :rnayfihen wbe treated-in warm Water, :oiled ,if {it is :to be transparent, "or powdered and .:packed -for storage.

;In thoseiinstances where the plastic is of such character -that; it does-not. adhere quite-so tightly .',tfO tvhe mold, itimay'ljbe advisable to.:f.orm.one.or :two r coatings upon .the =n1old before the spring is y .placedon-ithe' mold. lnsome .instancesti't has been found that one dipping, in which the spring is contacted will provide a sufiicientanchorage forthelspringtoitheiplastic-to permit rolling of theqskirtuportion of the diaphragm,.after which :finaladipping can be'made to seal the rolled skirt in rolled :position.

,In some 3 instances :it 'has 7 been found that "only roneidipping of vthe mold with the spring thereon ;is necessary to accomplish. both anchorage "of the springto theskirt an'dssealing of .the rolled skirt. That is, it is possible "to utilize the 'final .zdipping "of :the diaphragm for a-both. anchorage and sealing. :Insuchnnstances' the spring :may be .placed .ron :the mold ,just prior to .the finalco'at. The I mold then may be :given 2 the "final dip :by Iimmersingthe -mold, with .the :spring in position in :the plastic, .until :the spring is .icontacted and 'then :slowly iremoved. After partial drying and .while the final coat :is still tacky the skirt :may be .rolledwithlthe spring therein, the springcoming .to-rest-inlgroovezt before the finalcoathasicompletelydried. Upon drying "the'spring and skirt is sealed without the necessity of separately cefrom said mold.

2. The .method of making diaphragms which consists vin the (steps of positioning .a circular spring at a.prjedeterrninedposition upona mold, retaining such spring in .saidposition on. the mold, dipping the,m.old .whileretaining the spring in said -position into a liquid .plastic of .a synthetic organic polymer solution to a depth until the spring isncont'acted .by .the plastic, .removing the 40 mold .ahdspring .Ifrom-saidplastic, drying the coatedinold. toIforinia solid coating Ofthepl'astic on the. mold .with the spring-anchored to. the coating, rolling the. spring on theskirt portion of the, coating with the spring therein. toward the'rdome a predetermined .number of. complete. turns, redipping said I'noldlih'to the, plastic. solution. until the rolled skirt. portionis ,oontacte d. loythe, plastic and thenjwithdrawing .the. mold, drying the final coating, thusfsiniultaneously sealing the .latter in its rolled .pos'ition and increasing .the .thickness of w.the. coating, and thereafter removing-the .formed .diaphragmfromsaid mold.

.3.' The .rnethod of vmaking diaphragms from plastics .whichconsists in the-steps of d-ippinga .dome'shapped moldwith a..circular springrthereon while-thelat'ter isrretainedin positionon said .mold, .into. a.1iqu-id plastic. or a synthetic organic polymer .until such spring .is contacted by v.the ,plastic, removing said. moldand' spring -from.the plastic, .permitting .the film onsaid ,mold to:at least partially .solidi'fy, thus. forming a coating of plastic onthe. mold with the. c'oating-anchoredto the spring rollingthe skirt portion of said. coat- King and ,the spring withthespring therein upon the mold .toWa-rdlthe'tlome. of.-said.mo1d:to.aepredetermined position'onsaidmold, thereafter redipping .s-a-id moldinto the-plastic .l-li'ltih the-rolled .skir't ,portion .is contacted .and withdrawing the ln1old,. pe'rmitting the coat onsaidmoldtosolidify, .jthussealing .the rolledportion. of :the coat in its rolled position, and .thereaf ter. removingtheecompletedediaphragrmfrom saidmold.

y-4. The method of ma-king ndiaphragrr-rsif-rozn plastics which consists in the steps of simultaneously depositing a coating of a plastic of a synthetic organic polymer and anchoring said coating to a spring by dipping a mold with a circular spring positioned thereon into a liquid plastic until the spring is contacted by the plastic, removing said mold and spring from the plastic, permitting the coating on mold to solidify, rolling the skirt portion of said coating With the spring therein on the mold toward the end thereof to a predetermined position on said mold, thereafter simultaneously sealing the rolled portion and increasing the Wall thickness of the diaphragm by redipping said mold into the plastic until the rolled skirt portion is contacted by the plastic, removing the mold from the liquid plastic and REFERENCES CITED The following references are of record in the 5 file of this patent:

permitting the coating thereon to solidify, and 5 UNITED STATES PATENTS Number Name Date 2,024,539 Schmid Dec. 17, 1935 2,111,313 Clark Mar. 15, 1938 2,017,604 Mountford et a1. Oct. 15, 1935 2,283,238 Thompson May 19, 1942 2,314,262 Winder Mar. 16, 1943 2,371,883 Gammeter et al Mar. 20, 1945 

